For many years, electricians and technicians looking for a quick current reading have reached for the trusted Fluke T5 Electrical Tester, a per­sonal everyday tool seen in tool belts the world over. Now Fluke’s new T6 with FieldSense technology, improves the open fork functionality by allowing for ac current, ac voltage and frequency measurements to be made on one device at the same time, in real-time. The Fluke T6 Electri­cal Tester with FieldSense technology is the first handheld test tool using this new patent-pending technology.

Safer way to test voltage

FieldSense technology is a safer way to accurately measure voltage. Contacting electrical conductors with test leads or alligator clips requires metal-to-metal contact, which as any electrician or technician knows, carries the potential for arc flash. FieldSense eliminates that step. Because the measurement tool and the voltage source under test are iso­lated, the person performing the test is safer from potential electrical shock. This is performed by means of galvanic isolation or separation, the principle that isolates functions of an electrical current to prevent current flow. FieldSense takes a measurement of voltage without voltage flowing through the meter. Instead, the Fluke instrument, such as the T6-1000, senses an electrical field in the open fork to make the measurement, a safer method.

And since the measurement is performed through the cable’s insulation, users reduce exposure to metallic conductors and decrease the poten­tial for errors, or making contact with the wrong conductor.

How FieldSense works

FieldSense technology is truly a breakthrough in how voltage is measured. While the technology in the T5 detects a magnetic field to derive an ac current measurement, the new technology detects an electrical field. Fluke Research and Develop­ment teams first developed the open-fork voltage sensing technology, which involves transducing and calculating a known signal to derive mea­surements for the source voltage.

This was done by designing the device to gener­ate a reference signal of known amplitude and frequency. Then, when grounded, the resulting composite waveform is detected by an electronic sensor built into the tester. After amplification, processing and digital calculations, voltage and frequency measurements are derived.

The next step after developing voltage sensing, the teams were challenged to combine these two different physical phenomena – magnetic field sensing and electrical field sensing – into one device. After months of prototyping and test­ing the team was able to determine the optimal design so these two technologies could be paired together. The result is that for the first time in a Fluke meter, voltage and current can be measured and displayed at the same time.

What’s the difference between a voltage detector and FieldSense?

It’s important to distinguish the new FieldSense measurement technology from the variety of voltage detectors on the market. These voltage detectors range from pen style devices that light up when voltage is present to clamp meters that beep or vibrate when a voltage signal is present. The distinction is that a voltage detector generally shows users that voltage is simply present, whereas the FieldSense technology allows for actual, accurate voltage measurement.

How to use FieldSense technology

The open fork form factor is intuitive and easy to use. First, if necessary, separate individual hot and neutral wires. Then, slide the open fork over the hot wire (or neutral if the equipment is in operation). You now get a measure­ment. The open fork also makes it easier to isolate individual wires in a panel, which can be difficult when many wires are bundled. In many cases, the measurement can be made with one hand. That’s also a safer practice.

The benefits, include safer voltage measurements without having to connect meters in parallel; faster troubleshooting by being able to measure through the fork directly around a conductor, and the ability to make voltage and current read­ings at the same time.

Open fork test tools that can measure voltage, current and frequency are helpful for electrical troubleshooting workflows in many job roles. Electricians, electrical contractors, HVAC technicians, field service engineers and maintenance technicians will find the T6 extremely versa­tile for troubleshooting and maintenance while gaining access to previously inaccessible mea­surement points such as a junction.

Residential applications include measurement of loads on a branch circuit at a service panel; measurement of the load side voltage of a circuit breaker or fuse and the mapping outlets to breakers. Industrial applications include checking circuit loading at panel boards (including feeder cables, branch circuits, and neutrals) and the integrity of a grounding circuit, and the feed circuits coming into motors (up to 200 amps).